A Fault Location Algorithms Based On Two-terminal Data For Hybrid Transmission Lines

The application of hybrid transmission lines has been more and more widely used as the lack of land resources and the demands of beautifying the city appearance. Hybrid transmission lines fault location technique is able to accelerate the overhaul of fault lines and minimize the loss and impact caused by power failure. Therefore, studying hybrid transmission lines fault location technique is of great significance.In order to improve the accuracy of hybrid transmission lines fault location, and solve the problem of pseudo root, the paper used a distributed parameter model to improve the accuracy, and it also brought forward a improved algorithms based on two-terminal asynchronous data of fault location, which are applied to auto-reclosure strategy. MATLAB simulation showed that this location algorithms was unaffected with the factors of pseudo root, transition resistance, fault type, fault location and non-synchronous angle etc. to achieve fast and accurate fault location. The main work and achievements are as follows:1.Giving an overview of all the fault location techniques technologies and comparing their advantages and shortcomings, the subject of this study was based on a fault location algorithms based on two-terminal asynchronous data for hybrid transmission lines.2. In this paper, it made a mathematical model for hybrid transmission lines, and analyzed the causes of pseudo root according to voltage distribution along the transmission lines of hybrid transmission lines, then proposed an improved binary search algorithms. It proposed the parameter adaptive algorithms of hybrid transmission lines based on error analysis to reduce the impact of external factors.3. The paper analyzed common filter algorithms used in power system, it adopted an improved mobile data-window Fourier filtering algorithms with high precision and real-time to pretreatment the two-terminal data of power frequency before fault location. It converted three-phase component to sequence components by using symmetric component algorithms. The paper analyzed the non-asynchronous sampling of two-terminal data, and proposed an non-asynchronous Angle algorithms for hybrid transmission lines.4. Via MATLAB simulation, it verified this hybrid transmission lines fault location algorithms can effectively eliminate pseudo root, and measure the distance to fault quickly and accurately. Meanwhile, the simulation results demonstrated that the mobile data window Fourier filter can obtain the fundamental component from fault data with rapidity and high-precision. In addition the simulation also proved the existence of pseudo root.5. This paper also applied the fault location technique of hybrid transmission lines to coordination strategy of auto-reclosure to improve the safety and reliability of the power system. 6. Finally, make a summary of the whole paper, and put forward some prospect of further research.